feat: offline save-for-later + background sync for mark-cooked (v0.65.0)

Adds a "Save offline" button on the recipe page that force-refetches
the current page so the service worker's cache picks up a fresh copy
right now, plus a small IndexedDB-backed list (lib/offline-db.ts) of
what's been saved. The /offline fallback page now reads that list and
renders it instead of being a dead end with just a "go back" link.

Also fixes the service worker's network-first fetch handler, which
never wrote successful responses into its cache -- meaning the
existing offline page's claim that "recently visited recipes are
available" was never actually true. It populates the cache on every
successful GET now.

Background sync: marking a batch-cook dish as cooked while offline
(the only existing mark-cooked call site in the app) now queues the
request in IndexedDB instead of just failing, and registers a
Background Sync (public/sw.js's "sync" listener replays the queue)
for Chromium; lib/offline-queue.ts's online-event fallback covers
Safari/Firefox, which never fire that event at all. Both replay paths
read/write the same IndexedDB store so either one drains it.

Also removes apps/web/public/manifest.json, a stale static manifest
that layout.tsx used to link to before the previous commit pointed it
at the real generated route (app/manifest.ts) -- it had gone
unnoticed and unused since.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,15 @@
 
 All notable changes to Epicure are documented here. This file is mirrored in-app at `/changelog` (and in the admin dashboard) via `apps/web/lib/changelog.ts` — update both together.
 
+## 0.65.0 — 2026-07-21 00:45
+
+### Added
+- Save recipes for offline use: a "Save offline" button on any recipe pins it in the service worker cache so it opens with no connection. The offline fallback page now lists your saved (and recently visited) recipes instead of being a dead end.
+- Marking a batch-cook dish as cooked while offline no longer just fails — it's queued and synced automatically once you're back online (via Background Sync where supported, otherwise as soon as the app detects a connection).
+
+### Fixed
+- The service worker's network-first pages never actually populated its cache on success, so the offline page's claim that "recently visited recipes are available" wasn't true. It does now.
+
 ## 0.64.0 — 2026-07-21 00:30
 
 ### Fixed